The problem posed in the title seems both apparent and crucial. Its solution depends on how we understand the terms: culture and rhetoric. The definitions proposed in this study are not immediately obvious. Rhetoric should be understood following Quintilian's "Rhetorice est inveniendi recte et disponendi et eloquendi cum firma memoria et cum dignitate actionis scientia" [Quint., V.10.54]; culture, on the other hand, is cumulative and should be perceived as information obtained from others through mechanisms of social transmission, such as imitation, teaching, or language. In this situation, rhetoric possesses the tools for this social transmission. The tools of transmission will be both imitation (imitatio) and teaching and language, which are related to rhetoric (téchne rhetoriké). With this understanding of both terms—culture and rhetoric—it turns out that the latter is indispensable to culture. This article therefore provides evidence for this hypothesis.